moffatt



(No Model.) 3 SheetsSheet 1.

R. R. MOPPATT.

ELEGTRIG ARC LAMP. No. 258,244. Patented May 23,1882.

j I 2% I s4 v? Q \M I WITNESSES INVENTOR 3 Sheets-Sheet 2.

(No Model.)

R. R. MOFPATTf ELECTRIC ARC LAMP.

No. 258,244. 'Patented May 23, 1882.

INVENTOR N. PETERS. Phow-Lnlmgmphcr. \Vnshmghv. D. c.

3 Sheets-Sheet 3.

R. R. MOFPAT'T ELEGTRIGARG LAMP.

(No Model.)

Patented May, 23, 1882.

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INVENTOR WITNESSES N, PETERS. Phumuma m hu. Washinghm. D. c.

UNITED STATES PATENT OFFICE.

RICHARD It. MOFFATT, OF BROOKLYN, NEW'YORK.

ELECTRIC-ARC LAMP.

SPECIFICATION forming part of Letters Patent No. 258,244, dated May 23, 1882.

Application filed December 13, 1881.

To all whom it may concern Be it known that I, RICHARD It. MOFFATT, ofthe city of Brooklyn, county of Kings, State of New York, have invented new and useful Improvements in Electric-Arc Lamps; and I hereby declare the following to be a full and exact description of the said improvements, reference being had to the accompanying drawings, which form part of this specification. I

My invention relates to that class of electric lamps that produce light by means of the vol taic arc. Many of its details are shown anddescribed (but not claimed) in a prior application for a patent made jointly by myself and Sylvester Ohichester.

This invention consists in the combination, in an electric lamp, of a shunt or bypass circuit, an electro-magnet located therein, its armature, a device for breaking and closing said circuit, and means for varying the distance or space between said elect-ro-magnet and its armature for the purpose of causing the movement of the armature and the feeding of the carbons to take place at a desired time to keep the size of and the resistance in the are at or near any desired point.

It also consists in a means that will permit the armature to move a suificicnt distance for operating the feed mechanism before it will cause the breaking of the circuit, and will allow the armature to return to its normal position (or nearly so) before it will cause the closing of the said circuit again. This object can be accomplished by 'arious devices, sev eral of which are shown in the drawings.

It also consists in other novel features hereinafter specified.

In the annexed drawings, Figure lis an elevation or front view of the lamp with the side plate removed from the box-like apartment that contains the regulating mechanism. Fig. 2 represents a central sectional View of that part of the lamp that contains the regulating mechanism. Fig.3 is a cross-section of the same, taken on the line a: .r, Fig. 2. Figs. 4 and 5 are (reserved) cross-sections of the same, taken on the line w 00, Fig. 3. Figs. 6 and 7 are views illustrating different means for breaking and closing the circuit.

Similar letters of reference in the several figures indicate like or similar parts.

Letter A in the drawings denotes the frame (No model.)

pieces h hand h h, which serve to hold it in position and guide it in its operation.

jfare arms orextensions,in which are mounted a pinion, c, and an escapemcntwheel, c, as shown in the drawings.

h h are small (inside) lugs. c c are guiderods which extend from the top to the bottom of the case B, passing freely through the holes in the arms It and h, so that the frame II can have a movement upward and downward.

I is an adjusting-screw upon which the bottom of the frame H rests. Its objectis to control the movement of said frame and thereby the size of the arc.

M is an electro-magnet located in the main or are circuit, and is held in position, as shown in the drawings. on is its armature, which is secured to a tilting frame-piece, a, one end of which is pivoted to the case B. The other end operates within the frame H. 'An escapement, g, is pivoted the frame 12 and arranged to operate the escapement-wheel e.

N is an electro-magnet of high resistance, forming part of a sh untor by-pass circuit which avoids the are. n is its armature, secured to a tilting frame-piece, c, one end of which is pivoted to the case B. The other end is provided with projecting piecesp an(lp,which rest upon the bottom of the case B, as shown in Figs. 2 and 5.

K is a standard secured to the armature a. In its upper end is an opening, through which extends the lever which operates the escapement g.

o is'a tilting rod, one end of which is pivoted to the case B. The other end extends under the armature a, and makes contact by means of a metallic spring with a metallic strip or wire, 2, that is insulated from the case B. The contact-points may be made of platinum, carbon, or other suitable material. The

rod e is made and arranged in such a manner that it will press against the guide-rod c with sufficient spring-tension to hold it in any position that it may be placed in when not acted up on by the armature a or the projecting piece 1).

The electro-magnet N is provided with a screw-rod, 8, upon which are screw-nuts s 8. By this means it can be raised or lowered to increase or decrease the space between it and its armature, as maybe desired. Since screwnuts will also firmly clamp and hold the magnet in position at any desired point, by this arrangement of the electro-magnet the pressure of the armature on the contact-points always remains constant.

The frame A is properly insulated from the case B and the tube 0. An insulated wire (one end of which is marked extends through the hollow frameA and the case B to the electro-magnet M, hence to the case B,with which it has metallic contact. The wire that forms the shunt or bypass circuit has one of its terminals attached to the metal strip or wire 2. The other terminal has metallic contact with the frame A. The openings in the case B through which the wires pass are lined with insulating material. The spring to is intended to insure electric contact between the case B and the upper-carbon holder 1). A wire (one end of which is marked has metallic contact with the frame A. The electric current from the generator enters the lamp by the wire marked (flowing as indicated by the arrows in the drawings,) passes through the electromagnet M, the case B, the upper-carbon holder D, the carbon electrodes, the frame A, to the wire marked hence to the machine or generator. This is the main circuit in which the arcis formed and the light produced. Another passage for the current is through a shunt or by-pass circuit whichavoids the arc-namely, it passes from the case B through the rod 4;, its spring, the strip z, the eiectro-magnet N, the frame A, to the generator. As this shunt or bypass circuitis one ofhigh resistance, the greater quantity of electric current passes through the main or are circuit. As the carbonsareconsumed the sizeof the arc increases, and with it the resistance in the main circuit. This causes an increasing flow of current through the shunt or bypass circuit and a decreasing flow through the main circuit, which continues until the resistance in the main or are circuit is so great that the quantity of the current flowing through the shunt or by-pass circuit will be sufficient to cause the electromagnet (located therein) to attract its armature, the movement of which operates the feeding -mechanism, thus slightly reducing the space between the carbons, and also the resistance in the are, this operation being repeated as often as the resistance in the arc reachesa point that will cause the magnet to act and the feeding of the electrodes to take place.

In the operation of this invention it is neccssary that the armature a should have a sufficient movement upward to operate the feeding mechanism before it will act to break the circuit, (which allows it to fall,) and it is also necessary that it should return to (or near) its normal position before it will act to close the circuit again. In practice I find that it this is not provided for by means substantially such as those herein described the principle upon which it is based-i. 0., the automatic breaking and closing of the shunt or bypass circuit by the magnetic action of an electromagnet located therein-is practically inoperative.

In carrying out this invention various means or devices can be employed that will operate successfully the automatic breaking and closing of the shunt or bypass circuit by the mag netic action of an electro-magnet located therein to operate mechanism that will feed the carbons as they are consumed. The tilting rod a, (herein described and shown,) with its connections, is a simple device for accomplishing this end. Figs. 6 and 7 illustrate other means for this purpose. In Fig. 6, a is a metallic contact-weight, against which a spring, 0, presses with sutlicient force to retain or hold it at any point on the rod 0 against its own gravity, but

not against the force of the moving armature a. In Fig. 7 the metallic contact-weight a is arranged to slide upon a plane, and is operated by means of a lever acted upon by the moving armature a. it is held in position at any point by its own gravity, which is readily overcome by the force of the moving armature. In practice I have used a simple yielding spring that will follow up the contact-point with the armature as it is attracted until the necessary movement of the latter operates the feeding mechanism, when it breaks contact. This device, though operative, does not give entire satisfaction, for it closes the circuit again when the armature reaches that pointon its return where itwas when the circuit was broken. Said point being near to the magnet causes the latter to again not with a force that prevents the armature from returning to its normal position.

The operation of this invention is as follows: When the circuit is complete (with the generator) and the electric current flows the armature m is drawn upward by the eleetro-magnet M, raising the free end of the frame a, eugages the escapement g with the escapementwheel 0, and, pressing upon the lugs h, raises the frame H, the rack carbon-holder D, with its carbon, thus separating the electrodes,when the are will appear. As the carbon electrodes are consumed in the arc, the resistance increases therein, when the current flowing through the shunt or derived circuit increases (in proportion to the resistance in the are or main circuit) until the electro-magnet N has sufficient magnetic power to raise its armature a, which movement will raise the end of the escapement lever, causing the escapement g to allow the wheel 0 to move a limited distance (the weight of the carbon-holder being motive power) and the space between the carbons to be reduced a very little, which likewise reduces the resistance in the are. WVhen the armature a has raised a sufficient distance to insure the operation of the escapement g and wheel 0 it causes the provision p to act upon and to raise the end of the rod o, so that it will have no metallic contact with strip z,which will break the flow of current through the shunt or derived circuit, causing the magnet N to become non-active, when the armature it falls back to its normal position, in doing which it carries with it the free end of the tilting rod 4), (which has been kept from falling by its spring tension or pressure upon the rod 0,) thus making metal contact between the rod '0 and strip 2 and closing or completing the circuit again, when the electro-magnet N becomes active, and will repeat its operation when the resistance in the are and the strength of current in the shunt-circuit are increased. This continues while the light is in operation.

As it is a matter of great importance that the feed movement should take place at a time when the resistance in the arc is very great and near to the limit of the clectro-motive force in the current to maintain it, so as to produce light of maximum intensity, it is necessary that the poles of the electromagnet N should be placed at a proper distance from its armature a. This is accomplished by means of the screw-nuts t and t t'. By this arrangement the arc can be kept at any desired point, and many lamps may be operated successfully in the same circuit.

When the arc is broken by accident or intent the armature m, frame v, and frame H fall until the latter will rest upon the end of the adjusting-screw I, when the escapement g is withdrawn from the wheel 0, and the carbonholder will move downward until the electrodes touch,when the circuit is again complete, and the magnet M acts as hereinbefore described, re-establishingtheare. Whenthecurrentisnot flowing and the lamp non-active, the carbonholder can be moved freely up and down as the escapement is withdrawn from the wheel c. The size of the arc in starting the light is controlled by the adjusting -screw I, as will be readily understood.

Having thus fully described the nature, construction, and operation of my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In an electric lamp, the combination of the electro-magnet N, forming part of a derivedcircuit, its armature n, a device for breaking and closing said circuit, the moving frame I-I, escapement g, escapement-wheel e, pinion e, racked carbon-holder a, and means for allowing the armature to move a sufficient distance to insure the working of the escapement and the operation of the feed mechanism before breaking the circuit, and which also permit said armature to return to or near its normal position before closing said circuit, substantially as specified.

2. In an electric lamp, the combination of an elcctro-magnet, N, forming part of a derived circuit, its armature n, a device for breaking and closing said circuit by said magnet, mechanism for feeding the carbons, and means for moving and adjusting the magnet N for the purpose of increasing or diminishing the space between said magnet and its armature, substantially as specified.

3. In an electric lamp, the combination, with the carbon-holder D, of the moving frame H, guide-rods c 0, wheel 0, escapement g, armature-frame c, and the electro-magnet M, substantially as and for the purpose specified.

4. In an electric lamp, the combination of the carbon-holder D, the moving frame H, wheel a, guide-rods c 0, arm attire-frame o, electro-magnet M, and the adjusting-screw I, substantially as and for the purpose specified.

It. It. MOFFATT.

Witnesses:

GEORGE OocnnAN, S. OHIoHEs'rnR. 

